The present invention relates to a mechanical riser connector to be used in subsea operations. There are a number of presently known riser connectors many of which require diver assistance during connecting and disconnecting operations. However, there are other riser connectors which do not require diver assistance. For example, U.S. Pat. No. 4,138,148 does not require diver assistance since it is automatically connectable and is releasable by internal means activated by hydraulic pressure. My co-pending application Ser. No. 57,342 discloses a riser connector which may be remotely activated by a shifting tool.
However, the present invention is considerably different than prior riser connectors in that it connects automatically and locks without the use of a shifting tool, and it disconnects through purely mechanical operation. Such mechanical operation is performed by a novel shifting tool. None of the prior art riser connectors are operable in this manner. The present invention also avoids inadvertent disconnection caused in some riser connectors by the passage of objects, such as flow line pigs, through the bores of the riser members. The riser connector can only be disconnected by movement of the shifting tool in the bore of the riser connector first in one longitudinal direction followed by movement in the other longitudinal direction.